Washing Machine Water Level Fault Detection via Tub Movement
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Solution Overview
Problem
Conventional washing machine water level detection systems can produce erroneous pressure readings due to sensor malfunctions, such as blockages or bending, leading to overfilling or underfilling issues, as they fail to accurately detect water levels during drain cycles.
Innovation Solution
A washing machine system incorporating a measurement device to monitor the movement of the wash tub, in conjunction with a water level detection system using a pressure sensor, to identify discrepancies between tub movement and water level measurements, thereby detecting faults in the pressure sensor system and ensuring accurate water level detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is used to detect water level, then water level detection is enabled, but the sensor may become blocked or malfunction causing erroneous readings
Solution Approach 1:
The system uses feedback from the measurement device detecting tub movement to verify the accuracy of pressure sensor readings. When the tub movement indicates the sump is empty but the pressure sensor indicates water remains, the system identifies this discrepancy as a fault condition, enabling continuous verification of sensor reliability through operational feedback.
Solution Approach 2:
The measurement device acts as an intermediary verification mechanism. Instead of relying solely on the pressure sensor, the system introduces a second independent measurement method (tub movement detection) to cross-validate the water level status, thereby resolving the reliability issue of the pressure sensor.
2Device complexity
If the pressure sensor is used without fault detection, then the system is simpler, but overfilling or underfilling occurs due to sensor errors
Solution Approach 1:
The controller continuously monitors the correlation between tub movement data and pressure sensor readings during drain cycles. This feedback mechanism enables fault detection without requiring complex additional hardware, as it utilizes existing operational data to verify sensor accuracy and prevent overfilling or underfilling.
3Productivity
If the pressure sensor readings are not verified, then the system operates faster, but water level detection accuracy deteriorates due to sensor blockages
Solution Approach 1:
The system performs preliminary verification of pressure sensor accuracy by analyzing tub movement characteristics during the drain cycle. This preliminary check occurs automatically as part of the normal drain operation, enabling fast water level verification without adding significant time to the drain cycle while ensuring measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the identification of faults in the water level detection system, preventing overfilling or underfilling by cross-checking tub movement with pressure sensor readings, thus ensuring reliable water level monitoring and maintaining optimal wash cycle performance.
Implementation Method 1
water level detection systems may include pressure sensors coupled to pressure hoses on the sump for detecting the water pressure for determining the water level
Implementation Method 2
a measurement device configured for measuring movement of the wash tub
Data Source
AI summary
A washing machine appliance is provided including a sump positioned at a bottom of a wash tub for collecting wash fluid, a drain pump assembly for selectively draining the sump, a measurement device configured for measuring movement of the wash tub, and a water level detection system comprising a pressure sensor fluidly coupled to the sump. A controller is configured to operate the drain pump assembly to drain the wash fluid, measure the movement of the wash tub using the measurement device, measure a water level within the sump using the water level detection system, and identify a fault condition in the water level detection system upon determining that the measured movement indicates that the sump is empty and the measured water level indicates that the sump is not empty.